Synthesis of a novel(99m)Tc labeled GE11 peptide for EGFR SPECT imaging

摘要

Purpose This study investigated a novel SPECT agent for the noninvasive imaging of EGFR-overexpressing tumors. Methods The EGFR-targeting peptide GE11 was synthesized with the introduction of four amino acids (GGGC) to its C-terminal to act as a strong chelator and radiolabeled using(99m)Tc. The radiochemical yield of the(99m)Tc-peptide-GE11 were evaluated using RP-HPLC. Cellular assays of the probe were performed on two NSCLC cell lines: A549 (high expression) and H23 (low expression). Biodistribution and SPECT imaging were performed in BALB/c nude mice bearing A549 and H23 NSCLC xenografts. Results The(99m)Tc-peptide-GE11 was prepared at high efficiency with radiochemical yield of 98.40 +/- 1.00 % and it showed favorable stability. The cellular uptake was significantly higher in A549 than in H23 at all time points (especially at 1 h, which was 10.34 +/- 0.72 and 2.04 +/- 0.18, respectively). A nearly 56% reduction in probe uptake was observed after pretreatment with excess unlabeled peptides. The performance of SPECT imaging and biodistribution demonstrated higher uptake of the(99m)Tc-peptide-GE11 in A549 xenograft than in H23 xenografts. Conclusion The new SPECT tracer(99mT)c-peptide-GE11 showed EGFR specificity, favorable pharmacokinetics and great potential for EGFR-targeted imaging.